David Montes
  F. Labarga, A. Lopez-Gallifa et al.
  
  Universidad Complutense de Madrid
  
  Quantifying the chromospheric activity of M dwarfs from visible and near-infrared CARMENES spectra
  
  In this contribution we use the visible and near-infrared CARMENES spectra taken until now to analyse in detail the temporal variability of the chromospheric activity level and quantify the effect of the stellar jitter in the radial velocity determinations. In addition to the well known optical chromospheric activity indicators as the Na I D1, D2 HeI D3, H_alpha and Ca II IRT lines  we also investigate the behavior of some others as the HeI 10830 AA, P_gamma and P_beta lines that are included in the near-infrared spectral range covered by CARMENES. The chromospheric contribution in these lines has been determined using the spectral subtraction technique, that is by subtraction of a synthesized stellar spectrum constructed using artificially rotationally broadened, radial-velocity shifted, and weighted spectrum of an inactive star chosen to match the spectral type and luminosity class of the active star under consideration.